4 ms·

Not bit-for-bit reproducible. Package builds can be nondeterministic, binaries can have embedded timestamps (e.g, build time), and so on. They should be semant

Not bit-for-bit reproducible. Package builds can be nondeterministic, binaries can have embedded timestamps (e.g, build time), and so on. They should be semantically equivalent, but it's not fully guaranteed.

dd_ 4y ago
You're not wrong overall, but your example is. In the build environment, the current time is set to the epoch which removes that variability. An upcoming feature of nix is content addressed builds which use the output hashes to determine the store path. This should make it much more transparent which builds are reproducible and which are not.
- Filligree 4y ago
  > In the build environment, the current time is set to the epoch which removes that variability. The amount of time per build can vary. Embedded timestamps will all be in January 1970, but even a single second difference means the binaries are no longer bit for bit identical -- and that assumes the embedded timestamp isn't microseconds.
  - infogulch 4y ago
    I think you're assuming that the timestamp only starts at the epoch and still advances in real time, which is not necessarily true.
    - Filligree 4y ago
      If it didn't advance, that would cause trouble for some build systems. So yes, I'm assuming it does.